In most retail environments the customer selects various items for purchase and brings these items to an operator for checkout. The operator enters the price of each item selected, as well as a code particular to the item, into a point-of-sale terminal which then calculates the total amount the customer must pay. After payment is received the point-of-sale terminal calculates any change owing to the customer and produces a written receipt for the customer. Over the last two decades many retail products have been manufactured to contain a machine readable bar code. In response, many retail environments have incorporated an optical scanner into their point-of-sale systems. The operator is able to save time by scanning purchased items rather than having to manually key in price and product information. When the operator scans a product the optical scanner sends a signal corresponding to the product number to the data processing component of the point-of-sale terminal system. In the latter resides a product lookup table which quickly provides the price and the description of the scanned item.
Many inventions have been proposed over the last two decades to automate the point-of-sale terminal by having the customer scan the item himself/herself and then place the item on a checkout weighing receptacle. Since many items have predetermined weights, the point-of-sale terminal system need only compare the actual weight of the product placed on the checkout weighing device with the weight given by the product lookup table (i.e., along with the price and description information) to assure that the item placed on the checkout weighing receptacle is indeed the item scanned.
One early prior art system for automated checkout is described in Ehrat U.S. Pat. No. 3,836,755. Ehrat's invention consists of a shopping cart which contains a scanning and weighing apparatus and which in conjunction with an evaluation system evaluates the correspondence of weight with product designation. Another prior art system for automated checkout is described in Clyne U.S. Pat. No. 4,373,133. Clyne's invention consists of providing each customer's shopping cart with an electronic recording unit which is used by the customer to scan each item selected for purchase. The recording unit can contain a product lookup table to enable it to obtain weight and price information. When the customer wishes to check out, his/her collection of items is weighed to verify that the actual total weight corresponds with the total weight calculated by the electronic recording unit. One important limitation of Ehrat's and Clyne's inventions is their poor ability to deal with products not having a machine readable code. Another limitation is the risk of customer fraud if the customer easily substitutes a more expensive item having the same weight.
Improved systems for automated checkout are described in Mergenthaler U.S. Pat. No. 4,779,706, Johnson U.S. Pat. No. 4,787,467 and Humble U.S. Pat. No. 4,792,018. The Mergenthaler and Johnson inventions are quite similar. At a self-service station customers scan and weigh items (where weight is automatically checked against produce code) and then place items into a new cart (Johnson) or a bag (Mergenthaler) which is on a weighing receptacle. The new cart or new bags are then brought to a checkout station where it is verified that the weight of the cart or bags has not changed. The Humble invention passes items on a conveyer through a light tunnel after scanning. Not only is weight determined and verified against product number, but the product's dimensions can also be determined and verified against product number thereby making substitution of similar weight items difficult. The customer's items accumulate at the end of the light tunnel where they must later be bagged and presented to an operator for payment. To prevent customers from not scanning items and placing them at the end of the light tunnel for bagging, the Humble invention suggests the use of an electronic surveillance system in the pedestrian passage about the system.
The above inventions all have serious limitations with respect to customer fraud, shopping efficiency, non-coded products and use by nonexperienced users. In the Mergenthaler and Johnson patents, customer fraud remains an important problem as customers can scan a cheap item at the self-service station, discard it and immediately substitute a more expensive similarly weighing item. Despite the Humble patent's use of the light tunnel to determine item shape in addition to weight, the customer need only place an item at the bagging area without scanning it. The electronic surveillance system suggested by the Humble patent is not economical for retail enviroments such as supermarkets. As noted in the Shapiro article, "shoppers could conceivably put groceries directly from their carts into their shopping bags." In the Mergenthaler and Johnson patents, little attention is paid to shopper efficiency (as opposed to operator efficiency). Customers must handle items repeatedly to place them from one weighing station to another. The Humble invention also does a poor job with respect to shopper efficiency. After having scanned and placed all the purchased items on the conveyor, the customer must once again handle all the items during the bagging operation. The Johnson invention does make a limited provision for items not possessing a machine readable code by allowing customers to enter a code or price value. However, the items are not verified in any way by the invention. The Humble invention pays more attention to products not containing a machine readable. Customers are presented with selection on a computer screen and the invention attempts to verify the dimensions of the item correspond with the selection made. However, such correspondence is very limited. As a result, as the Shapiro article points out, "Fruits and vegetables present considerable problems . . . an employee is stationed in the produce department to weigh fruit and affix a coded label for the system to read." The Johnson and Mergenthaler inventions pay scant attention to user friendliness-an important consideration for non-experienced users. The Humble invention pays more attention to user friendliness with the incorporation of a touch-activated display screen. Nonetheless, as the Shapiro article notes, . . . "not delivered the promised labor savings . . . CheckRobot says one cashier can handle three to eight lanes. But because of the need to help confused customers . . . a cashier assigned to every two lanes and other employees hover around the machines to help customers."